The Atlantic Ocean surface circulation, and however that changes, has implications for how rainfall changes on continents, says study in scientific journal Nature Communications. Photo: AFP

Changes in ocean currents in the Atlantic Ocean influence rainfall in the western hemisphere and the two systems have been linked for thousands of years, according to a study published on Friday. The study by scientists at the University of Texas at Austin was published in the scientific journal Nature Communications.

The research is significant because the detailed look into Earth’s past climate and factors that influenced it could help scientists understand how they may influence climate today and in the future.

“The mechanisms that seem to be driving this correlation [in the past] are the same that are at play in modern data as well. The Atlantic Ocean surface circulation, and however that changes, has implications for how the rainfall changes on continents,” said the study’s lead author, Kaustubh Thirumalai, who had conducted the research while doing his PhD at the UT Austin Jackson School of Geosciences.

The study stressed that the Atlantic Ocean surface circulation is an important part of the Earth’s global climate, moving warm water from the tropics towards the poles.

An official statement explained that “the foundation of the research involved tracking the changes in ocean circulation in new detail by studying three sediment cores extracted from the seafloor of the Gulf of Mexico in 2010 during a scientific cruise”.

It stated that the samples give insight into factors that influenced the strength of the ocean current in about 30-year increments over the past 4,400 years.

“If we go back in increments of 30, we’re well-positioned to understand things on the order of centuries. And the question we decided to ask was what can those reconstructions of temperature and salinity tell us about the greater Atlantic Ocean surface circulation,” added Thirumalai.

The results indicate that in the present and the past, the Atlantic Ocean surface currents correlate with rainfall patterns in the western hemisphere.

“This finding is important for two reasons. It shows that a correlation exists between the currents and rainfall patterns, and that the correlation is evident in data sets that cover different time scales. It was remarkable,” Thirumalai said.

“These patterns that are based on decadal analysis of modern data and the hydroclimate proxies that give the salinity in the oceans and the rainfall on land, seem to show the same picture,” he added.

“The study demonstrates a robust century-scale link between ocean circulation changes in the Atlantic basin and rainfall in the adjacent continents during the past 4,000 years… And hence it provides a baseline for predictions on how that part of the climate system may behave in the future,” said University of Texas Institute for Geophysics director Terry Quinn, co-author of the study.